import { MILLISECONDS_A_MINUTE, MIN } from '../../constant'
var REGEX_VALID_OFFSET_FORMAT = /[+-]\d\d(?::?\d\d)?/g
var REGEX_OFFSET_HOURS_MINUTES_FORMAT = /([+-]|\d\d)/g

function offsetFromString(value) {
  if (value === void 0) {
    value = ''
  }

  var offset = value.match(REGEX_VALID_OFFSET_FORMAT)

  if (!offset) {
    return null
  }

  var _ref = ('' + offset[0]).match(REGEX_OFFSET_HOURS_MINUTES_FORMAT) || ['-', 0, 0],
    indicator = _ref[0],
    hoursOffset = _ref[1],
    minutesOffset = _ref[2]

  var totalOffsetInMinutes = +hoursOffset * 60 + +minutesOffset

  if (totalOffsetInMinutes === 0) {
    return 0
  }

  return indicator === '+' ? totalOffsetInMinutes : -totalOffsetInMinutes
}

export default (function (option, Dayjs, dayjs) {
  var proto = Dayjs.prototype

  dayjs.utc = function (date) {
    var cfg = {
      date: date,
      utc: true,
      args: arguments,
    } // eslint-disable-line prefer-rest-params

    return new Dayjs(cfg) // eslint-disable-line no-use-before-define
  }

  proto.utc = function (keepLocalTime) {
    var ins = dayjs(this.toDate(), {
      locale: this.$L,
      utc: true,
    })

    if (keepLocalTime) {
      return ins.add(this.utcOffset(), MIN)
    }

    return ins
  }

  proto.local = function () {
    return dayjs(this.toDate(), {
      locale: this.$L,
      utc: false,
    })
  }

  var oldParse = proto.parse

  proto.parse = function (cfg) {
    if (cfg.utc) {
      this.$u = true
    }

    if (!this.$utils().u(cfg.$offset)) {
      this.$offset = cfg.$offset
    }

    oldParse.call(this, cfg)
  }

  var oldInit = proto.init

  proto.init = function () {
    if (this.$u) {
      var $d = this.$d
      this.$y = $d.getUTCFullYear()
      this.$M = $d.getUTCMonth()
      this.$D = $d.getUTCDate()
      this.$W = $d.getUTCDay()
      this.$H = $d.getUTCHours()
      this.$m = $d.getUTCMinutes()
      this.$s = $d.getUTCSeconds()
      this.$ms = $d.getUTCMilliseconds()
    } else {
      oldInit.call(this)
    }
  }

  var oldUtcOffset = proto.utcOffset

  proto.utcOffset = function (input, keepLocalTime) {
    var _this$$utils = this.$utils(),
      u = _this$$utils.u

    if (u(input)) {
      if (this.$u) {
        return 0
      }

      if (!u(this.$offset)) {
        return this.$offset
      }

      return oldUtcOffset.call(this)
    }

    if (typeof input === 'string') {
      input = offsetFromString(input)

      if (input === null) {
        return this
      }
    }

    var offset = Math.abs(input) <= 16 ? input * 60 : input
    var ins = this

    if (keepLocalTime) {
      ins.$offset = offset
      ins.$u = input === 0
      return ins
    }

    if (input !== 0) {
      var localTimezoneOffset = this.$u ? this.toDate().getTimezoneOffset() : -1 * this.utcOffset()
      ins = this.local().add(offset + localTimezoneOffset, MIN)
      ins.$offset = offset
      ins.$x.$localOffset = localTimezoneOffset
    } else {
      ins = this.utc()
    }

    return ins
  }

  var oldFormat = proto.format
  var UTC_FORMAT_DEFAULT = 'YYYY-MM-DDTHH:mm:ss[Z]'

  proto.format = function (formatStr) {
    var str = formatStr || (this.$u ? UTC_FORMAT_DEFAULT : '')
    return oldFormat.call(this, str)
  }

  proto.valueOf = function () {
    var addedOffset = !this.$utils().u(this.$offset)
      ? this.$offset + (this.$x.$localOffset || new Date().getTimezoneOffset())
      : 0
    return this.$d.valueOf() - addedOffset * MILLISECONDS_A_MINUTE
  }

  proto.isUTC = function () {
    return !!this.$u
  }

  proto.toISOString = function () {
    return this.toDate().toISOString()
  }

  proto.toString = function () {
    return this.toDate().toUTCString()
  }

  var oldToDate = proto.toDate

  proto.toDate = function (type) {
    if (type === 's' && this.$offset) {
      return dayjs(this.format('YYYY-MM-DD HH:mm:ss:SSS')).toDate()
    }

    return oldToDate.call(this)
  }

  var oldDiff = proto.diff

  proto.diff = function (input, units, _float) {
    if (input && this.$u === input.$u) {
      return oldDiff.call(this, input, units, _float)
    }

    var localThis = this.local()
    var localInput = dayjs(input).local()
    return oldDiff.call(localThis, localInput, units, _float)
  }
})
